1. Field of the Invention
The present invention relates to a technique of searching for nodes in a network and more particularly to a node-search method, device and medium on which a node-search program is recorded for searching for nodes in a network configured with a plurality of domains which are connected through a mutual network connection device.
2. Description of Related Art
In a network, a plurality of addressable devices, which are called nodes, are connected. For example, work stations, personal computers, printers, scanners, router, etc. are used as a node. In this kind of network, it is difficult to always know all existing nodes. Therefore, it is sometimes necessary to search for the existence of a certain node. For example, searching for a node which performs a specific service.
For this purpose, it is possible to design a network in which a node which performs a specific service in the network returns its name and status in response to a broadcast from a specific port number. For example, by setting a host computer such that it broadcasts from the above-described specific port number when the power is turned ON or when starting to print, it is possible to search for a node which performs a specific service, such as a printer for printing.
On the other hand, there are networks configured with a plurality of sub networks connected by an interworking unit (IWU) for example a router. In such a network, the broadcast from a certain sub network cannot normally be transferred over the router. Therefore, with the method described above, it is not possible to search for service providing nodes in sections connected through the IWU.
For example, suppose a network in which a sub network A and a sub network B are mutually connected through a router is configured. The subnet mask for the sub networks A and B is 255.255.255.0, the address of the router for the sub network A is xxx.yyy.22.255, and the address of the router for the sub network B is xxx.yyy.33.255. In such a network configuration, the broadcast address from a node (host) connected to the sub network A to within the sub network A is xxx.yyy.22.255. However, the router does not transfer a broadcast packet containing this broadcast address to the sub network B.
Accordingly, depending on the broadcast described above from a node in the sub network A, there may exist a problem in that it is not possible to obtain a response from a node in the sub network B.